For most programming I could see this mainly leading to bad variable names, but for mathematical modelling we often want to keep code fairly consistent with how we would write a model in a paper or documentation.

Also, the lack of case sensitivity and namespaces exacerbates the issue of good variable naming for large projects. From a programming point of view, I would like long self-documenting names, but these can make complicated equations difficult to read. Local namespaces might solve the same need as a larger character set.